Three dimensional (3-D) graphics systems are used for providing, for example, video or liquid crystal displays (LCDs) of aeronautical charts and other digitized visual information. Performance requirements in such systems demand, among other things, 3-D color graphics in real time, the ability to allow solid objects to remain visible behind transparent objects, high throughput of massive amounts of data and volume clipping of pixels (i.e. the ability to view a scene sliced along the Z axis representative of depth in conventional three-dimensional space). Conventional memories do not operate at high enough speeds to meet such requirements. In particular, no VLSI or other devices are believed to be known in the art which can generate 3-D color graphics in real time for a 20 Hz, 512 x 512 display.
The invention overcomes the apparent deficiencies of prior art devices by providing an asynchronous memory interface to maximize system throughput in a 3-D color graphics display system. In addition, all calculations are carried out in a pipeline so that a translucent, Z-buffered pixel can be written every 1 to 2 memory cycles.
The invention also provides an ability to partition memory which increases effective memory bandwidths while minimizing hardware.